This invention generally relates to the field of pressure relief and more particularly to self-adjusting pressure relief seating systems and to corresponding methodologies.
Particularly in the field of healthcare, there has been a long felt and profound need to provide pressure relief for immobile or otherwise confined patients. For a tremendous variety of reasons, many patients must withstand long periods of bed rest or other forms of confinement, such as use of a wheelchair or other accommodating but restrictive support arrangement. In those instances, there is a tremendous risk that exposures to excess pressures, or longer term exposures to relatively lower pressure levels, can result in painful and even dangerous sores and other conditions.
Literally an entire segment of the healthcare industry is directed to the study and treatment of various tissue traumas, such as decubitus ulcers. Tissue damage can be monitored and rated, with progressively higher ratings warranting more involved treatment approaches. Consequently, the healthcare industry perceives and evaluates treatment options on the basis of their ability to address conditions at such different stages or ratings.
Some patient conditions to be addressed are not initially caused by excess pressure damage. For example, burn patients often have critical and even life threatening tissue care needs, but which did not originate from an excess pressure condition. Again, the initial condition of the patient is also ratable, which tends to dictate the measure of response.
Still further patients or others may have special needs. For example, injured patients, such as hip fractures or the like, may require special support care during a recovery period. Still other patients may have more long term specialized needs, such as amputees, who may have pressure sensitive areas and pressure points not accounted for by a support arrangement designed for a patient having weight dispersed over all limbs.
Literally scores of products, based on various technologies, have sought to address the constantly ongoing problem referenced above. As addressing the higher rated problems is, in general, technically more difficult, the costs of available treatments tend to rise in proportion with the rating magnitude of the problem.
Generally speaking, while cost containment has always been of concern in the healthcare industry, it has recently become a much more significant issue. As a net result of various forces acting with a goal of reducing costs, it is possible that the treatment needs (whether preventative or curative) of specific patients may run the risk of being inappropriately or even inadequately addressed.
Over time, as in any sort of industry, efforts have been made to simultaneously improve both quality (in the sense of product performance) and price. Typically, it can be difficult to simultaneously achieve both such goals, especially whenever product performance improvement comes at the expense of more entailed and sophisticated technologies. In addition, it is frequently the case that achieving top performance (i.e., optimized pressure relief or dispersion) is highly challenging, regardless of the available technology, at any cost. One contributing factor is the tremendous variation in patient needs which must be potentially met by a particular product (i.e., support system or methodology).
Typically, various support systems have made use of resilient support bodies, such as strips or blocks of foam, or some other support bladder containing a specific fluid. Mattress technologies, in general, have often made use of other resilient support media, such as springs, slats, or various support fillers, such as ticking. Different gases, often such as air, or various liquids have been used, including relatively viscous liquids, such as gels. In some instances, combinations of the above various technologies have been used.
As an effort to provide various cost effective designs applicable in different circumstances, there has generally been a progression in the sophistication of various products. For example, a repeating pattern such as convolutions may be readily formed in a resilient foam product for providing a resilient mattress supplement. See, for example, U.S. Pat. No. 4,686,725 entitled "Mattress Cushion with Securement Feature." While various repeating surface patterns are readily produced, more complicated repeating surface patterns have been provided in efforts to improve product performance over convoluted pads. See, for example, U.S. Pat. No. 4,901,387 entitled "Mattress Overlay with Individual Foam Springs."
One aspect of support systems, especially concerning those for use with recumbent patients, is that they are faced with distinctly different loading requirements along the longitudinal axis thereof. In other words, certain body areas of a patient will be heavier than others, thereby generally requiring greater support in such longitudinal areas if pressure relief is to be optimized.
As a result, various support pads have sought to provide sectionalized support. One such resilient foam pad making use of a uniform patterned surface, though with differential resilient support responsive to different loads, is U.S. Pat. No. 5,007,124 entitled "Support Pad with Uniform Patterned Surface."
As foam surface patterns become more sophisticated, there is a corresponding increase in the difficulty of producing such articles. One example of a three section foam mattress is U.S. Design Pat. No. 336,400, entitled "Foam Mattress Pad." Another example of a still more complicated foam mattress surface, typically requiring a computer controlled cutting machine for production, is U.S. Pat. No. 4,862,538, entitled "Multi-Section Mattress Overlay for Systemized Pressure Dispersion."
Still further examples of various resilient foam support pads and the like, and certain aspects of manufacture thereof, are shown by U.S. Pat. No. 4,603,445; U.S. Pat. No. 4,700,447; U.S. Design Pat. No. D307,688; U.S. Design Pat. No. D307,689; U.S. Design Pat. No. D307,690; U.S. Pat. No. 5,025,519; U.S. Design Pat. No. D322,907; and U.S. Pat. No. 5,252,278. Generally speaking, as support surface designs become more entailed, they become more difficult and more expensive to produce. At the same time, regardless of the manufacturing cost, they provide a generally static or preset response to loading changes, i.e., changes in the weight of the patient being supported in a specific region of the pad. Such variations may occur due to the variations among patients, or simply to the movement of an individual patient.
Other technologies involving fluid filled support bladders of various sorts may be incorporated into different types of systems regarded as either static or dynamic. Typically, what is meant by a static system is that the fluid level within a particular support chamber is sealed or otherwise relatively unchanged (or constantly replenished against losses). The pressure dispersion offered with such a system is thus, in at least one sense, analogous to the preestablished response expected with fixed resilient foam systems. However, it will be apparent to those of ordinary skill in the art that a fluid filled chamber approach, even in a static condition, would provide hydraulic fluid flow performance not found in a resilient foam system. Of course, the net pressure relief performance of any system or methodology encompasses various factors.
One example of a pressure relief support system utilizing fluid filled chambers is shown by U.S. Pat. No. 5,070,560, entitled "Pressure Relief Support System for a Mattress." In such patent, sealed longitudinal air cylinders are provided in the shape of a mattress, otherwise having various transverse slats and/or foam strips or members. Such a support system offers air dispersion pressure treatment in a static design which avoids the relative extremely high cost and other negative factors often associated with active air bed systems.
Highest rated pressure relief support systems typically involve beds having a plurality of fluid filled chambers, the internal pressures of which are maintained at a constant pressure by a relatively higher technology dynamic system approach. Specifically, each fluid filled support element may be associated with its own control valve, alternately permitting ingress and egress of fluid. Various pressure sensitive detection devices typically may be utilized in a feedback control system for determining that an excess pressure condition (or a subpressure condition) exists. Thereafter, the control technology is operative for bleeding off excess pressure by selected valving operation (such as dumping excess fluid into a reservoir arrangement) or for actively pumping in additionally needed fluid.
As such, the above higher technology systems require various motors, pumps, valving systems, sensory feedback arrangements, and control systems for all the foregoing. Due to their complicated construction and design, such beds are typically very expensive as to initial purchase or rental cost. They can also be complicated and expensive to maintain due to the prospect of frequent failure of numerous moving mechanical parts, and due to the extensive training which an operator or maintenance person would be required to undergo.
Also, there is the prospect of highly undesired heat transfer to a patient, due to operation to the above-referenced motors, pumps and other systems. Still further, the construction and design of such overall systems often require specialized bed frames not otherwise usable with typical mattresses.
The disclosures of the above-referenced United States Patents are fully incorporated herein by reference, all of which such Patents are commonly assigned.